The Association Between Human Immunodeficiency Virus and Bacterial Vaginosis and Metronidazole Treatment Failure for Trichomonas vaginalis

Background Trichomonas vaginalis (TV) is a common sexually transmitted infection. High rates of repeated infections have been observed, particularly among women living with human immunodeficiency virus (HIV). Trichomonas vaginalis frequently cooccurs with bacterial vaginosis (BV). The purpose of this study was to determine if coinfections with TV, BV, and HIV could lead to differential treatment failure outcomes. Methods Data were pooled from 2 prior randomized control trials comparing 2 g oral single-dose versus 500-mg twice daily oral 7-day dose metronidazole for the treatment of TV in HIV infected and HIV uninfected women. Trichomonas vaginalis rates 1-month postcompletion of treatment were compared by arm, HIV and BV status after removing those who had sexual reexposure, and/or did not complete their treatment. Results Data for 795 subjects were included in the study, of which 76 (9.6%) experienced treatment failure. In the final multivariable model, which included treatment dose, HIV status, and BV status, odds of treatment failure infection in the 7-day dose group were lower than the odds in the single dose group (odds ratio, 040; 95% confidence interval, 0.23–0.68). Treatment failure was lower in the multidose arm compared with single dose for both HIV-infected (4.0% vs 10.3%; P = 0.0568) and HIV-uninfected (7.3% vs 15.4%; P = 0.0037). Neither HIV nor BV was associated with higher treatment failure. Conclusions Human immunodeficiency virus infection and BV status did not significantly alter the rate of repeat infection for either single dose or 7-day dose metronidazole. Among all women, 7-day metronidazole lowered the odds of treatment failure.